ORA-12154 TNS error for ODBC connection via Excel

I have set up an ODBC connection via the Admin tools under control panel and it connects fine.

However, when I try to use the same connection to update from Excel, I receive the error ORA-12154: TNS: could not resolve the connect identifier specified.

I have validated that the tnsnames.ora file is in my current path.

I'm using the Oracle in instantclient10_2 driver to create the ODBC Data Source.

Any help would be SOOOO appreciated!

Thanks!!
Andrea